1. Field of the Invention
The invention relates to a method and the means of delineating zones on the surface of thermoplastic gratings.
2. Brief Description of the Prior Art
Surfaces which comprise molded thermoplastic gratings are well known in the prior art and include for example the recreational, ball-playing surfaces described in U.S. Pat. No. 3,438,312; see also the recreational surfaces described in U.S. Pat. Nos. 3,174,411 and 3,616,104. When these surfaces are employed, for example, as tennis courts they are made up of a plurality of square, unitary, elastic, molded thermoplastic sheets having a plurality of support legs on the lower surface. The plurality of square units, which resemble grates, are interlocked together along their edges to form the tennis court; see for example U.S. Pat. No. 4,054,987.
Prior hereto, the delineation of zones such as backcourt, forecourt and sidelines of the recreational playing surfaces made up as described above was affected by making two or more different square units of a contrasting color. These contrasting color units, when properly assembled, set off or delineated different zones; see for example the delineation achieved by the method of U.S. Pat. No. 4,045,022.
The prior art methods of delineating zones on surfaces of thermoplastic gratings have not been entirely satisfactory in all respects. For example, if one wishes to change a given delineation of zones, it is necessary to disassemble the assembled surface and re-assemble it in the desired pattern of colors. The present invention obviates this particular problem of the prior art and enables one to quickly and efficiently change any given delineation without disassembly of the surface. In addition, by the method of my invention, the individual thermoplastic grates may all be molded in a single color, reducing manufacturing and inventory costs.